This Flash animation is a 3D IFS animation drawn by Krzysztof Marczak, a fractal programmer and artist living in Lodz, Poland.

In mathematics, Iterated Function Systems or IFS are a method of constructing fractals; the resulting constructions are always self-similar.
IFS fractals, as they are normally called, can be of any number of dimensions, but are commonly computed and drawn in 2D.
The canonical example is the Sierpinski gasket, also called the Sierpinski triangle.

This video was drawn by Marczak in a program called Mandelbulber (written by Marczak) to convert 2D IFS fractals into 3D animations.
His website is: